Exhaust system for a diesel engine

ABSTRACT

An exhaust system for a high-performance diesel engine in which at least one of the engine cylinders exhausts directly into a turbocharger associated with the engine and the balance of the engine cylinders exhaust into regions of lower pressure in a main pipe in communication with the turbocharger. The system provides the best features of a constant velocity and a constant pressure system.

United States Patent von Hoevel et al.

[54] EXHAUST SYSTEM FOR A DIESEL ENGINE [75] Inventors: Edmund H. vonHoevel; Robert A.

Bolte, both of Jeannette, Pa.

[73] Assignee: Hanlon & Wilson Company,

Jeannette, Pa.

[22] Filed: Oct. 18, 1971 [21] Appl. No.: 189,948

[52] US. Cl. 60/13, 60/323 [51] Int. Cl. F02b 37/04 [58] Field of Search60/13, 323

[56] References Cited UNITED STATES PATENTS 3,618,313 11/1971 Zehnder60/13 3,077,071 2/1963 Leichtfuss. 60/323 2,730,861 l/l956 Biichi 60/132,899,797 8/1959 Birmenn 60/13 July 31, 1973 3,064,417 11/1962 Tryhom60/13 3,614,259 10/1971 Nefi' 60/13 FOREIGN PATENTS OR APPLICATIONS1,451,908 2/1970 Germany 60/13 Primary Examiner-Carlton R. CroyleAssistant Examiner-Warren Olsen Attorney-John M. Webb [57] ABSTRACT Anexhaust system for a high-performance diesel engine in which at leastone of the engine cylinders exhausts directly into a turbochargerassociated with the engine and the balance of the engine cylindersexhaust into regions of lower pressure in a main pipe in communicationwith the turbocharger. The system provides the best features of aconstant velocity and a constant pressure system.

8 Claims, 10 Drawing Figures 6L [7L 32 6L 5L I T l 34 BR IR 32 SR 38 SRPAIENIED JUL 3 1 i975 SNEEI 1 0F 4 PAIENIEU JUL 31 ms sum 3 or 4PATENTED Jul 31 SHEET l 0F 4 Qm Q Q Q Q Q Q Q 1 EXHAUST SYSTEM FOR ADIESEL ENGINE This invention relates to an exhaust system and moreparticularly to an exhaust manifold for a diesel engine of the typeemployed in railroad locomotives. The manifold design of the presentinvention generally improves performance of the engine exhaust system,especially through higher engine operating efficiencies, and promoteslonger engine and turbocharger life.

The present invention is an improvement over the two best known and mostcommonly used types of exhaust manifold systems, namely, the so-calledconstant velocity system and the constant pressure systern."

Briefly, the constant velocity system comprises a multipipe system, eachpipe of which has a constant flow cross section extending from an engineexhaust port, with which the pipe communicates, to the discharge end ofthe manifold which may be connected to the inlet of a turbocharger.Usually, each pipe in this system is connected to a pair of exhaustports; therefore, engine exhaust gas energy from one or more cylin dersmay be conveyed by each pipe assembly. Drawbacks of this system are thevelocity head losses in the pipe. These result from gas friction on thepipe wall as well as gas passing through elbow bends. Another drawbackis the direct impingement of all gas pulsations on the turbocharger,which shortens turbocharger life. On the positive side, the directdelivery of gases to the turbocharger gives the engine a greaterresponse to changes at the engine input. This leads to greaterefficiency and less waste of fuel during conditions of varyingoperation, such as acceleration.

The constant pressure system is essentially a pulse filtering system.The exhaust gases are passed into a main tube which serves as a plenumchamber. Depending on the pulse rate, pulse rise time, and size of themain tube, a particular filtering action will take place in the tube.This filtering action smoothes out the pressure pulses entering the tubeand gives a gas flow output from the tube that is continuously smoothand free of incoming pulsations. But the constant pressure system isslow to respond to immediate engine inputs. This, in turn, creates ahigh inefficiency during a time when speeds are being varied. However,under conditions of constant operation, the system operates withsatisfactory efficiency.

By integrating the two methods of delivering exhaust gases to aturbocharger, the best features of each system can be realized.

Our exhaust gas manifold comprises a number of pipes which directlyconnect the inlet ofa turbocharger associated with the engineto a givennumber of engine cylinders less than all of the engine cylinders. For example, in the preferred embodiment, four or six cylinders of a 16cylinder diesel engine are so connected. The majority of the cylindersdischarge exhaust gas into a main pipe of the manifold which isconnected at its discharge end to, and communicates with, the inlet of aturbocharger. The dimensions of the main pipe and the timing of theengine valves are so correlated that pressure fluctuations in themanifold are propagated internally. Specifically, the exhaust and intakevalves are open when the fluctuating gas pressure within the main pipeis minimum, permitting scavenging of the engine at lower blowerpressure. Each of the cylinders not directly connected by pipes to theturbocharger inlet is connected to the main pipe through a plurality ofexhaust gas pipes having a constant cross section. The cylindrical mainpipe has a large diameter relative to the diameter of the pipes whichare connected directly to the turbocharger inlet. Our manifold isdesigned to take advantage of the firing sequence of the cylinders inscavenging the engine by discharging the exhaust gases into low pressureregions of the manifold.

A more complete understanding of our invention will be gained from thefollowing description and the accompanying drawings wherein:

FIG. 1 is a plan view of one embodiment of our improved manifold for usewith a 16 cylinder V-type diesel engine showing the manifold and itsconnection with the cylinder exhaust ports and a turbocharger inlet;

FIG. 2 is an elevation view of the manifold of FIG. 1; FIG. 3 is a viewtaken along the lines III-Ill of FIG.

FIG. 4 shows a typical connection between the main pipe and a pipe froma cylinder;

FIG. 5 is a schematic view of the manifold of FIGS. 1 4 and itsconnection with the turbocharger inlet;

FIG. 6 is a plan view of a second embodiment of our invention;

FIG. 7 is an end view (rotated clockwise) on the lines VII-Vll of FIG. 6showing the manifold connnection with cylinders 1, 2, 3 and 4 only;

FIG. 8 is an end view (rotated 90 counterclockwise) on the linesVIII-VIII of FIG. 6 showing the manifold connection with the ports ofcylinders 5, 6, 7 and 8 only;

FIG. 9 is a view taken along the lines IXIX of FIG. 6 showing a part ofthe main pipe of the manifold and a means for supporting the manifoldadjacent the engine; and

FIG. 10 is a schematic view of our manifold showing its positionrelative to the engine exhaust ports and to a turbocharger inlet.

For convenience in referring to the drawings, the following conventionhas been adopted and is used throughout the description;

a. A cylinder is referred to by number and letter, i.e., 7R means theNo. 7 cylinder on the righthand side of the engine looking toward thedischarge end of the manifold.

b. The order of firing of a cylinder relative to all other cylinders isidentified: in the description, by an underscored number, i.e., 5 meansthe fifth cylinder to tire in sequence; and in the drawings, in atriangle, i.e.,A,

c. A cylinder which is directly connected to the turbocharger inlet atthe discharge end of the manifold is also underscored, i.e., 4L, the No.4 cylinder on the left side of the engine is connected by substantiallystraight pipe to the turbocharger inlet.

Referring to FIGS. 1 and 2, our manifold is adapted for connection to anengine such as a 16 cylinder V- block engine (not shown) the ports ofwhich connect to manifold flanges identifed by the attaching cylindernumber, i.e., 1R, 1L, 2R, 2L, 8R, 8L. A turbocharger inlet 10 isconnected to one end of the manifold through a cylindrical main pipe 12and cylinder pipes 14, 16 directly connected to cylinders IR, 4R, 1L and4L. The cylinder pipes, which are the same structure but in reversedposition, each comprise a curved section a, a bellows member b, arelatively long straight section 0, a tee section d which is connectedto port 1R,

or 1L, respectively, a second bellows member 2, and a flanged section fwhich is connected to flange 18 of pipe 20 which opens into the flaredmouth 22 of the turbocharger inlet 10.

The balance of the cylinders are indirectly connected to theturbocharger through the main pipe 12; that is, each of the cylindersother than IR and IL and 4R and 41.. discharges its exhaust into themain pipe 12 which is secured at one end to the turbocharger inlet andin direct communication with it. The drawings clearly show the structureand relative positions of the pipes which comprise our manifold. It willbe noted that a number of the exhaust pipes are supported along theengine by a connection at one end to an exhaust port and a connection atthe other end to a second gas pipe connected at its exhaust port toprovide a relatively short beam length for the pipe.

Cylinder ports 2R, 3R and EL, 3L exhaust into common pipes 24 and 26,respectively. The pipes 24 and 26 are connected into main pipe 12 nearthe turbocharger inlet. Bellows 28 and 30 are included in each of thepipes 24 and 26, respectively, to accommodate expansion and contractionof the sections upon change in temperature and pressure of the gasesflowing therein.

Cylinders 5 8, inclusive, are connected to their respective exhaustports and to the main pipe through pipes similar to pipes 24 and 26.Cylinder ports SR and SR are joined by pipe 32 to the main pipe 12 andcylinder ports 6R and 7R are connected to the main pipe by pipe 34.Bellows 36 and 38 are also provided in the pipes 32 and 34,respectively. An identical pipe structure on the opposite side of themanifold connects cylinder ports 5L, 6L, 7L and SL to the main pipe 12.

The location of the opening of the pipes from the exhaust ports ofcylinders 5, 6, 7 and 8 into the main pipe 12 is an important feature ofour invention. When the firing order of the cylinders is considered, itis seen that cylinders nearest the turbocharger end of the main pipe,i.e., the lower-numbered cylinders, exhaust first, leaving a lowpressure region therebehind. Cylinders later in the firing order, i.e.,those having the higher numbers, then fire discharging the exhaust gasesinto the low pressure region of the manifold behind a high pressurepulse, resulting in more effective scavenging of the total system.

Each of the pipes opening into the main pipe 12 is connected to it inthe manner typically shown in FIG. 4. The pipes are connected to aflange 40 of an elbow 42 which is secured, as by welding, along the edgeof an oval shaped opening into wall 44 of the main pipe 12. Each pipe issecured to two cylinder ports to carry the exhaust gases therefrom tothe turbocharger and each of these ports also supports the main pipe 12.Each length of pipe includes at least one bellows which allows forexpansion and contraction of the pipes and for relative change inposition due to high pressure exhaust pulsing of gases into and throughthe manifold system.

The preferred embodiment of this invention provides the best features ofa constant velocity manifold and a constant pressure manifold system.The schematic view of the system shown in FIG. 5 illustrates therelative locations of the elements of the system.

In a second embodiment of the invention, we have changed the relativepositions of some of the elements of the manifold system, and also havereduced the number of exhaust ports connected to the pipes leading intothe main pipe. As shown in FIG. 6 and using the same reference numeralsfor like elements previously disclosed, we have illustrated the cylinderexhaust ports of a typical 16 cylinder V-bank engine (not shown). A pipeis connected to each exhaust port and extends parallel to the rows ofcylinders along the engine. A number of such pipes are directlyconnected to an inlet 10 of a turbocharger (not shown) at theirdischarge ends, that is, the end opposite the exhaust ports to whichthey are connected.

Beginning at the discharge end of the manifold in FIG. 6, we have shownpipes 46 and 48 connected to the exhaust ports of cylinders IR and IL,respectively; pipes 50 and 52 connected to ports of 2R and 2L,respectively; and pipes 54 and 56 connected to ports 4R and 4L,respectively. Pipe 54 discharges through a portion of pipe 46 into theinlet 10 and pipe 56 discharges through a portion of pipe 48. Each pipe46, 48, 50, 52, 54 and S6 is of constant cross section and connects thecylinder exhaust port to which it is connected directly with the inletof the turbocharger 10.

A cylindrical main pipe 12 having a bellows 12a is connected at itsdischarge end to communicate with the turbocharger inlet and extendsalong the engine substantially parallel to the two rows of exhaust portsto a point adjacent the exhaust ports of cylinder 4. The main pipe isclosed at an end 58 opposite its discharge end and is supported (FIG. 9)by parallel vertically oriented gusset plates 60 having right angleflanges which are secured to end 58 and to the top of an engine block 62(shown in schematic), as by bolts 64 and 66.

Short pipes 68 and 70 open into the end 58 and connect cylinder ports SRand SL, respectively, to the main pipe 12. Pipes 72 and 74 open into themain pipe and connect it to cylinder ports 3R and 3L, respectively.Similarly, pipes 76 and 78, pipes 80 and 82, and pipes 84 and 86 connectcylinder ports 6R and 6L, 7R and 7L, SR and BL, respectively, to themain pipe 12. Each pipe 68 86, inclusive, is of constant cross sectionand connects its cylinder exhaust port to the main pipe 12 whichdischarges into the turbocharger inlet. Hence, each cylinder port 3R,3L, SR, 5L, 6R, 6L, 7R, 7L, and SK, SL is indirectly connected to theinlet 10.

A consideration of the manifold geometry shown in FIG. 6 of the drawingsindicates that six of the 16 cylinder exhaust ports are directlyconnected to the inlet of the turbocharger. Accordingly, approximately37.5 percent of the total exhaust energy is delivered directly to theturbocharger inlet assembly. The significance of this amount of energyis that positive acceleration under load is achieved.

Pertinent data has been set forth, in the Table, on a preferred manifolddesign for a turbocharged l6 cylinder, four cycle locomotive enginehaving a power rating of 2,500 brake horse power at 1,000 RPM; adisplacement of 9.0 bore by 10.5 stroke; and an engine firing order 1R,1L, 3R, 3L, 7R, 7L, 4R, 4L, 8R, 8L, 6R, 6L, 2R, 2L, 5R, 5L. A gas flowanalysis was predicated on these rated engine power conditions. Theexhaust gas temperature value used was 1,200F and the mean exhaust gaspressure was 44.7 psia. The engine displacement was calculated to be6.19 cubic feet. Using a turbocharger having a 3:1 pressure ratio, theintake volume was 9,270 SCFM of air. Exhaust gas weight flow wascaluclated to be 41,700 lbs/hr.

The following tabe correlates the cylinder number with the numericalsequence of firing, which in turn assures the desired and timed internalpressure fluctuations.

Distance Elapsed time from Time Cylinder when charge Engine willDischarge Time for will have passed Cylinder from Time Charge to intomain pipe To Main Zero (51.. pass into from time Firing Cylinder PipeInlet Disch. at time main pipe Zero" Order Number (In/Ft.) Zero" (Sec.)(Sea) (Sec.)

Exhaust Delivery Directly to Turbocharger 290-315 FtJSec. Avg. ManifoldPipe Gas Velocity.

It will be appreciated from the data set forth in the Table that thenon-interference, with each other, of every cylinder exhaust pulse;i.e., the balancing of exhaust energy to drive the turbocharger resultsin improved engine performance. Specifically, greater engineacceleration power boost can be achieved through the balance of theexhaust energy delivered to the turbocharger and an increase in the lifeof the turbocharger through a narrower band of exhaust temperature andpressure fluctuations. Lower cylinder head temperatures result throughimproved breathing of the engine. Effective scavenging of the engine ispromoted by the timed pressure fluctuations through the exhaustmanifold. In addition, lower blower pressures can be experienced withimprovement in the engine scavenging. Finally, engine fuel consumptionis improved, and cleaner exhaust emission achieved through moreeffective exhaust energy use.

A further example of the improved exhaust system for a diesel enginefollows:

To insure adequate exhaust gas velocities for improved turbochargerefficiency, the size of the main pipe and gas delivery pipes wereselected such that the average velocity range was from 290-315 ft./sec.Assuming a steady state gas flow and neglecting velocity pressure headloss since the design was predicated on a substantially straight gasflow, tight bends and abrupt cross sectional area changes being avoided,apreferred main pipe bore for receiving exhaust gas from cylinders SRand 31., SR and SL, GR and 6L, 7R and 71., and 8R and BL wasapproximately 7 inches 1D. The bore of the tubes interconnectingcylinders l and 4 were selected to be 3.07 inches I.D. These dimensionsinsured that pressure fluctuations within the pipe were propagatedinternally and did not interfere with discharge of the gases through themanifold to the inlet of the turbocharger. Moreover, by properlycontrolling the propagation of the fluctuations of the exhaust gaspassing through the turbocharger a more effective scavenging system isachieved.

Having described in detail certain embodiments of our invention, itshould be understood that the invention may otherwise be included in thescope of the appended claims.

We claim:

1. In a diesel engine having a plurality of engine exhaust ports, anexhaust gas manifold adapted to be connected to an inlet of aturbocharger for the engine comprising:

A. a main pipe adapted at one end for connection to the inlet of aturbocharger and closed at the opposite end;

B. a plurality of exhaust gas pipes of constant cross section less thanthe cross section of the main pipe, each of the pipes being connected toan exhaust port of the engine and adapted for direct connection to theinlet of the turbocharger;

C. a plurality of pipes having a cross section less than the crosssection of the main pipe, each of said pipes being connected to anexhaust port of the engine and to the main pipe; and

D. the total number of pipes adapted for direct connection to the inletof the supercharger being less than the total number of pipes connectedbetween the engine cylinder ports and the main pipe.

2. An exhaust gas manifold as set forth in claim 1 in which each of theexhaust gas pipes include, at a position along its length, at least onebellows member.

3. An exhaust gas manifold as set forth in claim 1 in which a number ofthe exhaust gas pipes are supported along the engine by a connection atone end to an exhaust port and a connection at the other end to a secondgas pipe connected to its exhaust port to provide a relatively shortbeam length for such pipe.

4. An exhaust manifold for a turbocharged diesel engine comprising:

A. a main pipe for connection at one end to an inlet of a turbochargerand closed at its opposite end;

B. a plurality of high gas velocity constant cross section pipes fordirect connection to cylinder ports of an engine and to the inlet of theturbocharger;

C. a second plurality of constant cross section pipes for connection tothe balance of the cylinder ports at one end and to the main pipe at theother;

D. the number of pipes for direct connection between cylinder ports andthe turbocharger inlet being less than the number of pipes forconnection between the balance of the cylinder ports and the cylindricalmain pipe.

5. An exhaust manifold as set forth in claim 4 in which the main pipehas its longitudinal axis for alignment with the inlet of theturbocharger and each of the pipes for direct connection between theports of the engine and the turbocharger has its axis parallel to theaxis of the main pipe.

6. An exhaust gas manifold as set forth in claim 4 in which the end ofthe main pipe opposite that to be connected to the turbocharger inlet issupported by means 7 8 for connection between said opposite end and ablock 8. An exhaust manifold as set forth in claim 4 in of an engine.which the pipes for direct connection between cylinder 7. An exhaustmanifold as set forth in claim 4 in ports and the turbocharger inletcarry less than 50 perwhich bellows are positioned in each of saidexhaust cent of the exhaust gases from the engine. carrying pipes forconnection to exhaust ports.

CERTlFlATE @F QRRECTION UNKTED STATES PATENT @FFICE l l Patent No.3,748,850 Dated July 31, 1973 Inventor(s) Edmund H. vonHoevel; Robert A.Bolte It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 2,1ine 53 "4L" should read "fig-q line 60 1R, 1L" should read --lR, 1 l J--;

line-63 "1R, 4R, 1L" should read "33, i 5,";

line 64 "4L" should read --4L--. Column 3,'l'1ne l "1L should read -5;

line 7 ."lR and IL and 4R" should read --l l3 and IL and 4R--;

line 8 "4L" should read --4L--. Column 4, line 13 "IR and IL" shouldread l l andil line 14 "2R and 2L" should read and Z L line 15 "4R"should read --4R--;

line 16 "4L" should read "Kl J;

line 26 "4" should read 2:

line 57 "1R, 1L" should read --il lL--;

line 57 "4R, 4L" should read 4R, ii;

line 58, "2R, 2L" should read Zl}, 2 l

line 67 "tabe'l should read --tab1e--. Column 5,line 67 "l and 4" shouldread "l and 4 Signed and sealed this th day of- November 1973.

(SEAL) Attest: I

' EDWARD M.FLETGHER,JR. RENE D. 'IEGTMEZYER Attesting Officer ActingCommissioner of Patents FORM PO-O (10-69) USCOMM-DC 60376-P69 u.s.GOVERNMENT PRINTING OFFICE I969 o-sss-au;

1. In a diesel engine having a plurality of engine exhaust ports, anexhaust gas manifold adapted to be connected to an inlet of aturbocharger for the engine comprising: A. a main pipe adapted at oneend for connection to the inlet of a turbocharger and closed at theopposite end; B. a plurality of exhaust gas pipes of constant crosssection less than the cross section of the main pipe, each of the pipesbeing connected to an exhaust port of the engine and adapted for directconnection to the inlet of the turbocharger; C. a plurality of pipeshaving a cross section less than the cross section of the main pipe,each of said pipes being connected to an exhaust port of the engine andto the main pipe; and D. the total number of pipes adapted for directconnection to the inlet of the supercharger being less than the totalnumber of pipes connected between the engine cylinder ports and the mainpipe.
 2. An exhaust gas manifold as set forth in claim 1 in which eachof the exhaust gas pipes include, at a position along its length, atleast one bellows member.
 3. An exhaust gas manifold as set forth inclaim 1 in which a number of the exhaust gas pipes are supported alongthe engine by a connection at one end to an exhaust port and aconnection at the other end to a second gas pipe connected to itsexhaust port to provide a relatively short beam length for such pipe. 4.An exhaust manifold for a turbocharged diesel engine comprising: A. amain pipe for connection at one end to an inlet of a turbocharger andclosed at its opposite end; B. a plurality of high gas velocity constantcross section pipes for direct connection to cylinder ports of an engineand to the inlet of the turbocharger; C. a second plurality of constantcross section pipes for connection to the balance of the cylinder portsat one end and to the main pipe at the other; D. the number of pipes fordirect connection between cylinder ports and the turbocharger inletbeing less than the number of pipes for connection between the balanceof the cylinder ports and the cylindrical main pipe.
 5. An exhaustmanifold as set forth in claim 4 in which the main pipe has itslongitudinal axis for alignment with the inlet of the turbocharger andeach of the pipes for direct connection between the ports of the engineand the turbocharger has its axis parallel to the axis of the main pipe.6. An exhaust gas manifold as set forth in claim 4 in which the end ofthe main pipe opposite that to be connected to the turbocharger inlet issupported by means for connection between said opposite end and a blockof an engine.
 7. An exhaust manifold as set forth in claim 4 in whichbellows are positioned in each of said exhaust carrying pipes forconnection to exhaust ports.
 8. An exhaust manifold as set forth inclaim 4 in which the pipes for direct connection between cylinder portsand the turbocharger inlet carry less than 50 percent of the exhaustgases from the engine.